diff --git a/ethcore/src/secret_store.rs b/ethcore/src/secret_store.rs
index e610fa65b..a7289f4e4 100644
--- a/ethcore/src/secret_store.rs
+++ b/ethcore/src/secret_store.rs
@@ -24,18 +24,8 @@ enum CryptoCipherType {
 	Aes128Ctr(U128)
 }
 
-enum KeyFileKdf {
-	Pbkdf2(KdfPbkdf2Params),
-	Scrypt(KdfScryptParams)
-}
-
-struct KeyFileCrypto {
-	cipher: CryptoCipherType,
-	Kdf: KeyFileKdf,
-}
-
 enum KeyFileVersion {
-	V1, V2, V3
+	V3(u64)
 }
 
 enum Pbkdf2CryptoFunction {
@@ -56,6 +46,22 @@ struct KdfPbkdf2Params {
 	prf: Pbkdf2CryptoFunction
 }
 
+#[derive(Debug)]
+enum KdfPbkdf2ParseError {
+	InvalidParameter(String)
+}
+
+impl KdfPbkdf2Params {
+	fn new(_json: &Json) -> Result<KdfPbkdf2Params, KdfPbkdf2ParseError> {
+		KdfPbkdf2Params{
+			dkLen: 0,
+			salt: H256::zero(),
+			c: 0,
+			prf: Pbkdf2CryptoFunction::HMacSha256
+		}
+	}
+}
+
 #[allow(non_snake_case)]
 // Kdf of type `Scrypt`
 // https://en.wikipedia.org/wiki/Scrypt
@@ -70,15 +76,157 @@ struct KdfScryptParams {
 	r: u32,
 }
 
-type Uuid = String;
+#[derive(Debug)]
+enum ScryptParseError {
+	InvalidParameter(String)
+}
+
+impl KdfScryptParams {
+	fn new(_json: &Json) -> Result<KdfScryptParams, KdfPbkdf2ParseError> {
+		Ok(KdfScryptParams{
+			dkLen: 0,
+			p: 0,
+			n: 0,
+			r: 0
+		})
+	}
+}
 
 enum Kdf {
 	Pbkdf2(KdfPbkdf2Params),
 	Scrypt(KdfScryptParams)
 }
 
+enum KeyFileKdf {
+	Pbkdf2(KdfPbkdf2Params),
+	Scrypt(KdfScryptParams)
+}
+
+struct KeyFileCrypto {
+	cipher_type: CryptoCipherType,
+	cipher_text: Bytes,
+	kdf: KeyFileKdf,
+}
+
+impl KeyFileCrypto {
+	fn new(json: &Json) -> Result<KeyFileCrypto, CryptoParseError> {
+		let as_object = match json.as_object() {
+			None => { return Err(CryptoParseError::InvalidJsonFormat); }
+			Some(obj) => obj
+		};
+
+		let cipher_type = match as_object["cipher"].as_string() {
+			None => { return Err(CryptoParseError::NoCipherType); }
+			Some("aes-128-ctr") => CryptoCipherType::Aes128Ctr(
+				match as_object["cipherparams"].as_string() {
+					None => { return Err(CryptoParseError::NoCipherParameters); },
+					Some(cipher_param) => H128::from(cipher_param)
+				}
+			),
+			Some(oter_cipher_type) => {
+				return Err(CryptoParseError::InvalidCipherType(
+					Mismatch { expected: "aes-128-ctr".to_owned(), found: other_cipher_type.to_owned() }));
+			}
+		};
+
+		let kdf = match (as_object["kdf"].as_string(), as_object["kdfparams"]) {
+			(None, _) => { return Err(CryptoParseError::NoKdfType); },
+			(_, None) => { return Err(CryptoParseError::NoKdfParams); },
+			(Some("scrypt"), Some(kdf_params)) =>
+				match KdfScryptParams::new(kdf_params) {
+					Err(scrypt_params_error) => return Err(CryptoParseError::Scrypt(scrypt_params_error)),
+					Ok(scrypt_params) => scrypt_params
+				},
+			(Some("pbkdf2"), Some(kdf_params)) =>
+				match KdfPbkdf2Params::new(kdf_params) {
+					Err(kdfPbkdf2_params_error) => return Err(CryptoParseError::Scrypt(scrypt_params_error)),
+					Ok(kdfPbkdf2_params) => kdfPbkdf2_params
+				},
+			(Some(other_kdf), _) => {
+				return Err(CryptoParseError::InvalidKdfType(
+					Mismatch { expected: "pbkdf2/scrypt".to_owned(), found: other_kdf.to_ownded()}));
+			}
+		};
+
+		let cipher_text = match as_object["ciphertext"].as_string() {
+			None => { return Err(CryptoParseError::NoCipherText); }
+			Some(text) => text
+		};
+
+		Ok(KeyFileCrypto {
+			cipher_text: Bytes::from(cipher_text),
+			cipher_type: cipher_type,
+			kdf: kdf,
+		})
+	}
+}
+
+type Uuid = String;
+
 struct KeyFileContent {
 	version: KeyFileVersion,
 	crypto: KeyFileCrypto,
 	id: Uuid
 }
+
+#[derive(Debug)]
+enum CryptoParseError {
+	InvalidJsonFormat,
+	InvalidCryptoVersion,
+	NoCryptoVersion,
+	InvalidKdfType(Mismatch<String>),
+	InvalidCipherType(Mismatch<String>),
+	NoCipherText,
+	NoKdfType,
+	NoKdfParams,
+	Scrypt(ScryptParseError),
+	KdfPbkdf2(KdfPbkdf2ParseError)
+}
+
+#[derive(Debug)]
+enum KeyFileParseError {
+	InvalidVersion,
+	UnsupportedVersion(OutOfBounds<u64>),
+	InvalidJsonFormat,
+	NoIdentifier,
+	NoCryptoSection,
+	Crypto(CryptoParseError),
+}
+
+impl KeyFileContent {
+	fn new(json: &Json) -> Result<KeyFileContent, KeyFileParseError> {
+		let as_object = match json.as_object() {
+			None => { return Err(KeyFileParseError::InvalidJsonFormat); },
+			Some(obj) => obj
+		};
+
+		let version = match as_object["version"].as_u64() {
+			None => { return Err(KeyFileParseError::InvalidVersion); },
+			Some(json_version) => {
+				if json_version <= 2 {
+					return Err(KeyFileParseError::UnsupportedVersion(OutOfBounds { min: Some(3), max: None, found: json_version }))
+				};
+				KeyFileVersion::V3(json_version)
+			}
+		};
+
+		let id = match as_object["id"].as_string() {
+			None => { return Err(KeyFileParseError::NoIdentifier); },
+			Some(id) => id
+		};
+
+		let crypto = match as_object.get("crypto") {
+			None => { return Err(KeyFileParseError::NoCryptoSection); }
+			Some(crypto_json) => match KeyFileCrypto::new(crypto_json) {
+					Ok(crypto) => crypto,
+					Err(crypto_error) => { return Err(KeyFileParseError::Crypto(crypto_error)); }
+				}
+		};
+
+		Ok(KeyFileContent {
+			version: version,
+			id: id.to_owned(),
+			crypto: crypto
+		})
+	}
+}